1. Technical Field
The present invention relates to an ethylene-xcex1-olefin copolymer which possesses various superior properties and a superior processability; a composition of the same; a film and a polar group-containing resin material of the same; and products and uses of the same. More concretely, the present invention relates to an ethylene-xcex1-olefin copolymer suitable for various packaging films manufacturing by means of T-die technique, inflation techniques, and the like, molded films such as a film for lamination, blow-molded products such as various containers manufactured by means of blow molding, injection-molded products such as various vessels, lids, containers, and the like, manufactured by means of injection molding, covering for electric wires, cables, steel pipes, and the like; a composition thereof; and a film and a polar group-containing resin material thereof. The present application is based on Japanese Patent Application No. Hei 10-173594, Japanese Patent Application No. Hei 10-197879, Japanese Patent Application No. Hei 10-197880, Japanese Patent Application No. Hei 10-226229, and Japanese Patent Application No. Hei 10-226231, the contents of which are incorporated herein by reference.
2. Background Art
The conventional, linear low density polyethylene (LLDPE) having a density of 0.89 to 0.94 g/cm3 comprises an ethylene-xcex1-olefin copolymer produced by means of using a Ziegler catalyst. This conventional LLDPE is superior in strength and toughness to a high pressure process low density polyethylene (HpLDPE) obtained according to a high pressure radical polymerization, and applied to various uses such as films, sheets, blow-molded products, injection-molded products, and the like.
However, the conventional LLDPE possesses a distinct disadvantage in that it is inferior with respect to its processability. Therefore, in the field of films such as packaging materials, improvements in the gap width of the die in a processing device, as disclosed in U.S. Pat. No. 4,243,619 (Union Carbide Chemicals and Plastics Technology Corporation, hereinafter referred to as UCC), in addition to blending of the aforementioned HpLDPE into a LLDPE, have been developed.
More recently, it has become highly desirable to improve the both the overall strength and the sealing strength (i.e., low temperature heat sealability) of an LLDPE, in order to increase the speed of the processing cycle, by means of high-speed filling, and also reduce the weight of the molded products.
In recent years, an ethylene-xcex1-olefin copolymer which exhibits an improved low temperature heat sealability and strength has been developed. This ethylene-xcex1-olefin copolymer is obtained by means of using a metallocene catalyst, the molecular weight distribution and composition distribution of which are extremely narrow, which serves to impart high strength. Such an ethylene-xcex1-olefin copolymer is disclosed in, for example, Japanese Patent Application, First Publication Laid Open No. Sho 60-35009 (WPI: 85-001577, U.S. Pat. No. 4,540,753/Exxon Chemical Patents Inc., hereinafter referred to as Exxon), Japanese Patent Application, First Publication No. Hei 3-502710 (WPI: 90-132257, U.S. Pat. No. 5,382,630/Exxon), Japanese Patent Application First Publication No. Hei 7-500131 (WPI: 90-134412, U.S. Pat. No. 5,250,612/The Dow Chemical Company, hereinafter referred to as Dow), Japanese Patent Application, First Publication No. Hei 7-500622 (WPI: 93-152427, U.S. Pat. No. 5,272,236, WO930822/Dow), Japanese Patent Application, First Publication Laid Open No. Hei 8-311260 (WPI: 96-507707, U.S. Pat. No. 5,798,427/UCC), Japanese Patent Application, First Publication Laid Open No. Hei 9-255724 (WPI: 96-435560, EP735060/UCC), Japanese Patent Application, First Publication No. Hei 8-505174 (U.S. Pat. No. 5,420,220/Mobil Oil Corporation, hereinafter referred to as Mobil), Japanese Patent Application, First Publication No. Hei 9-511003 (WPI: 95-351300, EP751967, WO95/26372/Mobil), and the like.
However, these conventional, ethylene-xcex1-olefin copolymers obtained by means of using a metallocene catalyst, (mLLDPE), possesses several disadvantages. For example, since their composition distribution and molecular weight distribution are extremely narrow, and their properties of viscosity and strength change dramatically according to the temperature, these copolymers pose the problems of having only a limited applicable range for the temperature, extrusion conditions, and the like during the processing process, in addition to an inferior processability. In addition, the aforementioned mLLDPE is inferior both with respect to its properties of thermal resistance, even after being processed to a molded product, and with respect to its heat sealability, due to the narrow range of temperatures which can impart the appropriate heat sealing strength.
Japanese Patent Application, First Publication No. Hei 6-509528, (WO93/03093/Exxon) discloses a heat-sealed product wherein the heat sealing initiation temperature is less than 93xc2x0 C., by means of using a polymer which possesses a narrow composition distribution of at least 50 on the composition distribution breadth index (CDBI). However, this heat-sealed product possesses improved properties of a low temperature heat sealability, but exhibits an inferior thermal resistance, and an inferior heat-sealing strength.
A blended composition of mLLDPE obtained by means of using a metallocene catalyst and HpLDPE, and film thereof are disclosed, for example, in Japanese Patent Application, First Publication No. Hei 9-511273, (WO95/27005/Mobil), Japanese Patent Application, First Publication Laid Open No. Hei 6-65442, (WPI: 93-407455, U.S. Pat. No. 5,594,071/Mitsui Petrochemicals Ind., Ltd.), Japanese Patent Application, First Publication Laid Open No. Hei 6-65443, (WPI: 93-407455, U.S. Pat. No. 5,674,945/Mitsui Petrochemicals Ind., Ltd.), Japanese Patent Application First Publication Laid Open No. Hei 6-136194, (WPI: 94-197254/Mitsui Petrochemicals Ind., Ltd.), Japanese Patent Application, First Publication Laid Open No. Hei 6-136196, (WPI: 94-197255/Mitsui Petrochemicals Ind., Ltd.), Japanese Patent Application, First Publication laid Open No. Hei 9-183816, (EP781789A2, WPI: 97-334856/Mitsui Petrochemicals Ind., Ltd.), Japanese Patent Application, First Publication Laid Open No. Hei 9-59440, (WPI: 97-248282/Toso Corporation), Japanese Patent Application, First Publication No. Hei 8-502532, (WPI: 94-151264, U.S. Pat. No. 5,562,958/Dow), and the like. Composition and films disclosed therein are superior in their processability, however, possess disadvantages such as having a narrow applicable range for the temperature at which an adequate heat sealing strength is exhibited, due to their narrow molecular weight distribution and composition distribution.
An ethylene-60-olefin copolymer, which improves on the aforementioned problems, is disclosed in Japanese Patent Application, First Publication No. Hei 8-325333, (WPI: 96-435559, U.S. Pat. No. 5,874,513/Nippon Petrochemicals Co., Ltd., a joint venture partner of the applicant of the present invention). This ethylene-xcex1-olefin copolymer is superior in low temperature heat sealability, hot tacking properties, and the like, but also displays an insufficient thermal resistance, processability, and the like.
In general, the thermal resistance of a polyethylene resin can be improved by means of increasing its density and the amount of components possessing high melting points. However, since the amount of components having a low melting point simultaneously decreases, the heat sealing initiation temperature also rises, and a deterioration in the clarity and reduction in flexibility, due to an increased elasticity, unavoidably result.
In order to solve the aforementioned problem, Japanese Patent Application, First Publication No. Hei 8-501812, (WPI: 94-118420, U.S. Pat. No. 5,376,439/Exxon), and Japanese Patent Application, First Publication No. Hei 9-505094, (WPI: 95-194055, U.S. Pat. No. 5,530,065/Exxon), disclose a method for mixing a polyethylene resin obtained by means of using a conventional, Ziegler catalyst, which exhibits a superior thermal resistance, and a polyethylene resin obtained by means of using a conventional, metallocene catalyst, which exhibits a superior mechanical strength and possesses a low heat sealing inhibition temperature.
However, the polyethylene resin obtained by means of using a Ziegler catalyst possesses a high heat-sealing initiation temperature, and exhibits an inferior mechanical strength. On the other hand, the polyethylene resin obtained by means of using a metallocene catalyst exhibits both an inferior thermal resistance and processability. Accordingly, the simple mixture of these two resins possesses a wider molecular weight distribution than the conventional, polyethylene resin obtained by means of using a metallocene catalyst, thus leading to an inferior mechanical strength. Similarly, the aforementioned mixture also exhibits both an inferior thermal resistance and processability compared to the polyethylene resin obtained by means of a using Ziegler catalyst.
On the other hand, in the field of sealant films molded according to extrusion processing, and the like, a film which exhibits a superior clarity, impact strength, low temperature heat sealability, heat sealing strength, anti-blocking properties, and the like, is highly desirable. Such a film is superior with respect to its gas-barrier properties, and is applicable to various packaging materials for pickles, dairy products, retort pouch foods, frozen foods, and the like; packing materials for pharmaceutical drugs, medical container, various liquid transporter, and the like; bottles; containers; and the like. Examples of the sealant film used in this field may include sealant films comprising a mLLDPE, obtained by means of using a metallocene catalyst. Such sealant films are disclosed in Japanese Patent Application, First Publication Laid Open No. Hei 8-157611, (WPI: 96-339289/Sekisui Chemical Co., Ltd.), a specific LLDPE obtained by means of using a single site catalyst is disclosed in Japanese Patent Application, First Publicatoin Laid Open No. Hei 9-137132, (WPI: 97-337244/Sekisui Chemical Co., Ltd.), Japanese Patent Application, First Publication Laid Open No. Hei 9-59442, (WPI: 96-435559/Nippon Petrochemicals Co., Ltd.), and the like. In addition, there is also a great demand to increase the speed of the processing cycle, thermal resistance, and the like, in this field as well. The present invention relates an improved version of the invention disclosed in Japanese Patent Application, First Publication Laid Open No. Hei 9-59442.
In addition, in the field of extrusion lamination processing, dry lamination processing, and the like, wherein a resin is coated onto a substrate, it is highly desirable to improve the productivity, adhesive strength, and thermal resistance. A composition for extrusion lamination, a multi-layered film, and the like, which comprise a mLLDPE obtained by means of a using metallocene catalyst, are disclosed in Japanese Patent Application, First Publication Laid Open No. Hei 7-26079, (WPI: 95-102014/Mitsubishi Chemical Corporation), Japanese Patent Application, First Publication Laid Open No. Hei 7-26080, (WPI: 95-102015/Mitsubishi Chemical Corporation), and Japanese Patent Application, First Publication Laid Open No. Hei 9-57916, (WPI: 97-208082/Mitsubishi Chemical Corporation).
In addition, one of the uses of molded products manufactured by means of lamination processing includes a release member. The release member may be used as an adhesive sheet, binder sheet, adhesive tape substrate, process sheet, and the like. Such a release member is disclosed in detail in Japanese Patent Application, First Publication Laid Open No. Hei 10-80972, (WPI: 98-254960/Nippon Petrochemicals Co., Ltd.). However, a release member possessing a higher productivity, adhesive strength, and thermal resistance, is highly desired. The present invention relates to an improved version of the invention disclosed in Japanese Patent Application, First Publication Laid Open No. Hei 10-80972.
Other uses of the molded product manufactured by means of extrusion lamination processing may include a paper-laminated member, and paper container using the aforementioned. Paper containers using mLLDPE obtained by means of using a metallocene catalyst are disclosed in Japanese Patent Application, First Publication Laid Open No. Hei 9-29868, (WPI: 97-160443/Dai Nippon Printing Co., Ltd.), Japanese Patent Application, First Publication Laid Open No. Hei 9-169068, (WPI: 97-388884/Dai Nippon Printing Co., Ltd.), Japanese Patent Application, First Publication Laid Open No. Hei 9-187900, (WPI: 97-419926/Dai Nippon Printing Co., Ltd.), Japanese Patent Application, First Publication Laid Open No. Hei 9-142455, (WPI: 97-346826/Toppan Printing Co., Ltd.), Japanese Patent Application, First Publication Laid Open No. Hei 9-193323, (WPI: 97-430480/Toppan Printing Co., Ltd.), and the like. However, a laminate and paper container, which possess a superior productivity, adhesive strength, and thermal resistance to these of the laminates and paper containers disclosed therein, are desired.
In addition, as a retort container, a medical container comprising LLDPE is disclosed in Japanese Patent Application, Second Publication No. Hei 5-59831, (WO86/002044/Baxter International Incorporated), and Japanese Patent Application, Second Publication No. Hei 6-14952, (WPI: 87-208701/Sinsozai Sogo Kenkyusho K. K.). In addition, a medical container comprising mLLDPE obtained by means of using a metallocene catalyst is disclosed in Japanese Patent Application, First Publication Laid Open No. Hei 9-99035, (WPI: 97-275661/Terumo Corporation), Japanese Patent Application, First Publication Laid Open No. Hei 9-155996, (WPI: 97-368349/Toso Corporation), and the like. In the field of retort containers, it is necessary that deformation and peeling of the heat-sealed portion not occur during the retort sterilization process of the films or containers, and the like, which are to be used. Accordingly, a thermal resistance of at least 110xc2x0 C. is desired for a retort container.
An electric insulating material used for electric wires and cables, comprising an mLLDPE obtained by means of using a metallocene catalyst, is disclosed in Japanese Patent Application, First Publication Laid Open No. Hei 8-111121, (WPI: 96-26550/Hitachi Cable, Ltd.), Japanese Patent Application, First Publication Laid Open No. Hei 8-111125, (WPI: 96-265524/Hitachi Cable, Ltd.), Japanese Patent Application, First Publication Laid Open No. Hei 8-222026, (WPI: 96-448060/Hitachi Cable, Ltd.), Japanese Patent Application, First Publication No. Hei 6-509905, (U.S. Pat. No. 5,246,783/Exxon), and the like.
However, these mLLDPE obtained by means of using a metallocene catalyst disclosed therein, possesses a limited range of appropriate temperatures and ejection conditions during the processing process due to their extremely narrow composition distribution and molecular weight distribution, in addition to the dramatic fluctuations in their properties of viscosity and strength depending on the temperature, which in turn leads to an inferior processability.
Known methods for improving such problems includes a method wherein a component with a different molecular weight is blended in the mLLDPE; and a method wherein the mLLDPE is obtained by means of multi-step polymerization, and the like. However, even if these means for improvement are used, the processability of the mLLDPE obtained by means of using a metallocene catalyst is not necessarily at a sufficient level. Another known method for improving the aforementioned includes one in which an ethylene polymer, obtained by means of using a metallocene, is blended with an ethylene polymer obtained by means of using a Ziegler catalyst or Phillips catalyst possessing a different molecular weight, which is disclosed in, for example, Japanese Patent Application, First Publication No. Hei 9-505094. However, the electric insulating material obtained according to this method possesses an insufficient dispersability, which leads to melt fractures and a decreased mechanical strength.
The inventors of the present invention disclose an electric insulating material possessing a low electrical activation energy, appropriate for an electric insulating material, by means of improving the aforementioned mLLDPE obtained by means of using a metallocene catalyst, in Japanese Patent Application, First Publication No. Hei 9-17235, (Nippon Petrochemicals Co., Ltd.). However, this electric insulating material also exhibits an insufficient processability. The present invention relates to an improved version of the invention disclosed in Japanese Patent Application, First Publication Laid Open No. Hei 9-17235.
In addition, non-polar polyethylene resins such as LLDPE, high density polyethylene, and the like, are basically inferior with respect to their adhesive properties to substrates such as other resins, metals and the like, and with respect to their compatibility with other resins, and the like. In order to impart adhesive properties to and improve the compatibility with polyethylene resins, a method is known for introducing a polar group of unsaturated carbonic acids and derivatives thereof into a polyethylene resin by means of polymerization, or grafting.
A modified-LLDPE using mLLDPE obtained by mean of using a metallocene catalyst is disclosed in Japanese Patent Application, First Publication Laid Open No. Hei 6-206947, (WPI: 94-275906/Mitsui Petrochemicals Ind., Ltd.), Japanese Patent Application, First Publication Laid Open No. Hei 6-207062, (WPI: 94-275961/Mitsui Petrochemicals Ind., Ltd.), Japanese Patent Application, First Publication Laid Open No. Hei 6-206946, (WPI: 94-275905/Mitsui Petrochemicals Ind., Ltd.), Japanese Patent Application, First Publication Laid Open No. Hei 6-207058, (WPI: 94-275960/Mitsui Petrochemicals Ind., Ltd.), Japanese Patent Application, First Publication Laid Open No. Hei 9-176391, (WPI: 97-399677), and a modified-specific ethylene-xcex1-olefin copolymer is disclosed in Japanese Patent Application, First Publication Laid Open No. Hei 9-235319, (WPI: 97-498357/Japan Polyolefins Co., Ltd.), and the like. However, the modified-LLDPE disclosed therein exhibits an inferior adhesive strength, and thermal resistance. The present invention relates to an improved version of the invention disclosed in Japanese Patent Application, First Publication Laid Open No. Hei 9-235319, (WPI: 97-498357/Nippon Petrochemicals Co., Ltd.).
Accordingly, the first object of the present invention is to provide a specific ethylene-xcex1-olefin copolymer, which exhibits a superior mechanical strength, optic properties, thermal resistance, and the like, compared with a LLDPE obtained by means of using a Ziegler catalyst; an equally favorable low temperature heat sealability, and clarity compared with the conventional, ethylene-xcex1-olefin copolymer obtained by means of using a metallocene catalyst; and a superior thermal resistance, heat sealing strength, and processability compared with the conventional ethylene-xcex1-olefin copolymer obtained by means of using a metallocene catalyst.
It is a second object of the present invention to provide a composition of said particular ethylene-xcex1-olefin copolymer, and other polyolefin.
It is a third object of the present invention to provide a molded product that is molded from said specific ethylene-xcex1-olefin copolymer, or composition thereof.
Examples of the molded product may include films, laminates comprising said film, release members using said laminate, containers, retort containers used for foods and medicine, paper containers, electric insulating materials, electric wires, cables, and the like. In particular, the present invention provides a superior processability, mechanical strength, and electric insulating properties to the aforementioned electric insulating material, electric wire, and cable.
It is a fourth object of the present invention to provide a resin material containing a polar group, which exhibits a superior thermal resistance, heat sealing strength, and processability, and imparts a superior adhesive properties to various substrates, and a superior affinity to various resins; and a laminate using the same.
In consideration of the aforementioned, the inventors of the present invention, after intense research, have disclosed an ethylene-xcex1-olefin copolymer possessing a relatively broad composition distribution, despite having a narrow molecular weight distribution, which exhibits a favorable tensile strength, impact resistance, low temperature heat sealability, and thermal resistance, and thereby achieves the aforementioned objectives.
in other words, the ethylene-xcex1-olefin copolymer of the present invention is obtained by means of polymerizing an ethylene and a C4-12 xcex1-olefin, and is characterized in satisfying the following conditions (A) to (E):
(A) a density in the range of 0.92 to 0.96 g/cm3;
(B) a melt flow rate (MFR) in the range of 0.01 to 200 g/10 min;
(C) a molecular weight distribution (Mw/Mn) in the range of 1.5 to 5.0;
(D) possessing only one peak in terms of the number of peaks observed in an elution temperature-eluted amount curve as measured by the continuous temperature raising elution fractionation (TREF) method, and from the integrated elution curve obtained by said elution temperature-eluted amount curve, the temperature difference T75xe2x88x92T75 and said density d both satisfy the relationship shown by formula a and formula b, wherein T25 is the temperature at which 25% of the total elusion is obtained, and T75 is temperature at which 75% of the total elution is obtained; and
T75xe2x88x92T25xe2x89xa7xe2x88x92300xc3x97d+285 (for d less than 0.950 g/cm3)
T75xe2x88x92T25xe2x89xa70 (for dxe2x89xa70.950 g/cm3)xe2x80x83xe2x80x83(Formula a)
T75xe2x88x92T25xe2x89xa6xe2x88x92670xc3x97d+644 xe2x80x83xe2x80x83(Formula b) 
(E) possessing one or two melting point peaks, and among these the highest melting point Tm1 and said density d satisfy the relationship shown by formula c.
Tm1xe2x89xa7150xc3x97dxe2x88x9217 xe2x80x83xe2x80x83(Formula c) 
This ethylene-xcex1-olefin copolymer possesses superior optical characteristics, mechanical strength, and thermal resistance over the LLDPE obtained by means of using a Ziegler catalyst. Moreover, while possessing the same low temperature heat sealability and transparency as an ethylene-xcex1-olefin copolymer obtained by means of using a conventional metallocene catalyst, this ethylene-xcex1-olefin copolymer in addition exhibits a superior thermal resistance, heat sealing strength, and processability when compared with the ethylene-xcex1-olefin copolymer obtained by means of using a conventional metallocene catalyst.
In addition, the resin composition according the present invention is characterized in comprising 1 to 99% by weight of the ethylene-xcex1-olefin copolymer described in the aforementioned, and 1 to 99% by weight of another polyolefin.
Accordingly, this resin composition exhibits superior optical characteristics, mechanical strength, thermal resistance, heat sealing strength, and processability.
In addition, a molded product comprising the ethylene-xcex1-olefin copolymer according to the present invention or composition thereof also exhibits superior optical characteristics, mechanical strength, thermal resistance, heat sealing strength, and productivity.
In addition, a film comprising the ethylene-xcex1-olefin copolymer according to the present invention or composition thereof also exhibits superior optical characteristics, mechanical strength, thermal resistance, heat sealing strength, and productivity.
In addition, the laminate, release member, container, retort container and paper container using the ethylene-xcex1-olefin copolymer according to the present invention or composition thereof exhibits a superior productivity, adhesive strength, and thermal resistance.
In addition, the electrical insulating material comprising the ethylene-xcex1-olefin copolymer according to the present invention or composition thereof exhibits a superior processability, mechanical strength, and electrical insulating properties.
Furthermore, the polar group-containing resin material according to the present invention is characterized in comprising one type of monomer unit selected from among (a) to (e) below in the resin component which comprises the ethylene-xcex1-olefin copolymer, wherein the concentration of the monomer unit ranges from 10xe2x88x928 to 10xe2x88x923 mol per one gram of resin component:
(a) a carbonic acid group or acid anhydride group-containing monomer;
(b) an epoxy group-containing monomer;
(c) a hydroxyl group-containing monomer;
(d) an amino group-containing monomer; and
(e) silane group-containing monomer.
The polar group-containing resin material formed in this manner displays a superior thermal resistance, heat sealing strength, processability, and exhibits a superior adhesiveness with respect to various substrates, in addition to a superior affinity for various types of resins.